1. Field of the Invention
The present invention relates to water treating devices and, more particularly, to a system in which hard water is softened and a reduction in the dissolved solids in the water is obtained.
2.Prior Art
Water softener systems presently in use are of the type in which hard water enters the top of a pressure tank through an inlet line and percolates through a bed of treatment material, such as zeolite, and passes out of the pressure tank through an outlet line having a mouth located proximate the bottom of the pressure tank. As the hard water percolates through the zeolite bed, an ion exchange takes place in which sodium ions held by the zeolite are exchanged for the hard metal ions in the water.
The water softening ability of the zeolite bed is gradually reduced and, after a predetermined quantity of water has been softened, the zeolite bed becomes depleted. The zeolite bed is thereafter regenerated by passing a brine solution through it so that the ion exchange process is reversed.
Prior to the regeneration cycle of a typical water softening system, the system goes through a backwash cycle in which hard water enters the pressure tank through the outlet line and percolates upward to leave the tank through the inlet line. Thus, the zeolite is agitated and any large deposits of debris carried into the pressure tank from the inlet line are flushed out of the pressure tank.
Reverse Osmosis water treatment systems in which water is passed through a semi-permeable membrane carried on a rigid structure such as a perforated metal tube and collected in a holding tank to filter out unwanted contaminants are known in the art. Such a system is disclosed, for example, in U.S. Pat. No. 3,616,929, issued Nov. 2, 1971, to Manjikian; such a system may be connected in tandem with a water softening system so that the reverse osmosis treatment system is either upstream or downstream of the water softening system. In either case the treatment system operates independently of the water softening system.
A disadvantage of such a reverse osmosis treatment system is that small particulate contaminants collect on the surface of the membranes to block the flow of water, thus necessitating periodic cleaning of the membranes. Other such systems have included a drain from the tank holding the membrane elements to provide a continuous flow of water past the elements, thus cleansing the membrane surfaces. This results in a substantial amount of water being wasted, however. Furthermore, prior art reverse osmosis treatment systems require a pressure tank which is separate from any softener system utilized therewith thus adding to the complexity and cost of the overall system. Accordingly, there is a need for a water softening and dissolved solid reduction system in which hard water is softened and dissolved solids removed therefrom within a single vessel, which system is easy to maintain.